This invention is the result of continuing development work on the basic concepts set forth in the three parent U.S. patent applications referenced hereinabove. This patent application should be considered to incorporate by reference all of the detailed description and background information contained therein, since for reasons of conciseness, total repetition will not be attempted here.
It is well-known that the single bypass ratio engines in use today have not reached their performance potential because the designs have been compromised to achieve satisfactory performance at several different flight conditions. For this reason, the obtaining of variable bypass ratio and variable engine cycle characteristics have been long sought goals of aircraft engine designers. Many schemes have been proposed, but most have not been successful or practical.